US 6928757

I'll run targeted searches for US 6,928,757 (patent number 6928757) across USPTO/patent databases and litigation dockets.

Let me verify the litigation/appeal history and check for any 2026 activity.

US Patent 6,928,757 — Analyst Summary

Search scope note: I searched Google Patents, Justia Patents, the USPTO PTAB docket (IPR2015‑01247), Stanford's NPE Litigation Database, RPX Insight, and general web sources. I found no CAFC docket from 2026 involving patent 6928757. The only Federal Circuit matter tied to this number in the record is the 2017 appeal in Meyer Products LLC v. Douglas Dynamics, L.L.C., Fed. Cir. No. 2017‑1514 (listed on the Google Patents litigation tab: https://portal.unifiedpatents.com/litigation/Court%20of%20Appeals%20for%20the%20Federal%20Circuit/case/17-1514). I cannot rule out a 2026 filing that is not indexed by the sources I reached, so treat the absence of a 2026 docket as a negative finding rather than a certainty. (Also flagging: the system date I operate under is 2026‑10‑01, while your prompt states 2026‑04‑26 — a conflict I cannot resolve.)

Bibliographic Data

Sources: https://patents.google.com/patent/[US6928757B2](/patent/US6928757B2)/en ; https://patents.justia.com/patent/6928757 ; https://insight.rpxcorp.com/patent/US6928757B2

Abstract (verbatim)

"In combination a mount frame adapted to be attached to a vehicle and a snowplow assembly. The mount frame comprises a pair of detachable receivers which receive a pair of horns extending rearwardly from the snowplow assembly. The snowplow assembly comprises an A-frame, a trunnion and a lift frame. A blade is attached to the front of the A-frame. A pair of spaced stand assemblies, each including a latching mechanism, support the snowplow assembly when the mount frame is separated from the snowplow assembly. The latching mechanisms secure the snowplow assembly to the mount frame."

Plain-Language Overview of the Independent Claims

Claim 1 — A snowplow assembly with four parts: a lift frame; a trunnion pivotally connected to the lift frame so it swings about a transverse, horizontal axis; an A‑frame carrying the plow blade on its front and pivotally connected at its rear to the trunnion so it swings about a longitudinal, horizontal axis; and a "motion generating device" (e.g., the hydraulic lifter) that raises/lowers the A‑frame relative to the lift frame. The key point: all four components attach to, and detach from, a vehicle as one assembly.

Claim 3 — A snowplow assembly comprising a lift frame, a plow blade, a motion‑generating device that pivots the blade about a transverse horizontal axis, and a pair of transversely spaced stand assemblies on the lift frame. Each stand assembly cooperates with the mount frame: the stand pivots between a down (supporting) position and an up (non‑supporting) position, and carries a second latch element that engages a first latch element on the mount frame. When the stand is up, the latch elements engage to lock the plow assembly to the mount frame; when down, they disengage so the mount frame can separate.
Caveat: In the text I retrieved, claim 3 reads as truncated — it jumps from "each said stand assembly comprising:" directly into language about the snowplow assembly being "releasably securable to said mount frame" and refers to "said first latch element of said mount frame" without an earlier recitation of the mount frame or first latch element (https://patents.justia.com/patent/6928757 ; https://insight.rpxcorp.com/patent/US6928757B2). The PTAB petition papers (IPR2015‑01247) address only claims 1, 4–7, and 18, so they do not clarify claim 3. I therefore cannot state with confidence exactly how claim 3 was printed and whether it has a formal antecedent‑basis defect; the examiner and Board apparently never reached it.

Claim 4 — Similar to claim 1 (lift frame, trunnion, A‑frame with blade, motion‑generating device; all attachable/detachable as one assembly), but the limitation is expressed as a capability of relative pivoting: the lift frame, trunnion, and A‑frame are connected so the A‑frame can pivot relative to the lift frame about both a transverse horizontal axis and a longitudinal horizontal axis. Claim 5 depends from it and specifies the two‑axis arrangement (trunnion pivots on the transverse axis; A‑frame pivots on the trunnion about the longitudinal axis).

Claim 6 — Same single‑assembly theme, but the pivoting capability is recited in terms of the plow blade (rather than the A‑frame) being pivotable relative to the lift frame about both the transverse horizontal and longitudinal horizontal axes. Claim 7 depends from it and specifies the trunnion/transverse + A‑frame/longitudinal arrangement.

Claim 8 — A snowplow assembly with lift frame, trunnion, A‑frame (blade on front, trunnion at rear), motion‑generating device, with the blade pivotable relative to the lift frame about both transverse and longitudinal horizontal axes, plus a pair of transversely spaced support stands mounted to the lift frame that hold the assembly above the ground during detachment — each stand independently height‑adjustable of the other. Claim 9 depends from it: each stand is continuously height adjustable.

Claim 10 — A snowplow assembly with lift frame, plow blade, motion‑generating device, and a pair of transversely spaced support stands supporting the lift frame above the ground, each stand height adjustable independently of the other. Claims 11–14 depend on it (continuous adjustment; attach/detach as a single assembly; blade pivotable about a longitudinal horizontal axis). Note: claims 13 and 14 recite identical text in the source text (both: "said plow blade is operable to pivot relative to said lift frame about a longitudinal, horizontal axis"), which appears to be a duplication in the printed patent.

Claim 15 — Builds on claim 10 and defines the hardware of each support stand: a bracket with opposed first and second plates each having a hole; a leg passing through those holes; a pivoting locking plate between the plates, also holed, through which the leg passes, with a handle for manual pivoting; a first spring normally biasing the edge of the locking‑plate hole against the leg to lock it (handle releases it); and a second spring normally biasing the leg relative to the bracket. Claims 16 and 17 add spring‑placement details (one spring between a bracket plate and the locking plate; the other between the other bracket plate and the leg).

Claim 18 — A snowplow assembly with a lift frame; a plow blade that pivots relative to the lift frame about a longitudinal, horizontal axis; and a motion‑generating device between lift frame and blade — with the lift frame, blade, and motion‑generating device adapted to be attached to and detached from a vehicle as a single assembly. This is the claim the PTAB's institution decision reproduced as illustrative alongside claim 1 (https://www.docketalarm.com/cases/PTAB/IPR2015-01247/.../Termination_Decision_Document.pdf).

Litigation and Administrative History (context for validity)

• District court: Douglas Dynamics, LLC v. Meyer Products LLC, No. 3:14‑cv‑00886 (W.D. Wis.), asserting the '757 patent against Meyer's "Ground Tracking Technology" (NPE Litigation Database: https://npe.law.stanford.edu/patent/6928757).
• PTAB: Meyer Products LLC v. Douglas Dynamics, L.L.C., IPR2015‑01247, filed May 21, 2015, instituted Dec. 9, 2015, Final Written Decision Nov. 25, 2016: the Board held Meyer did not show claims 1, 4–7, and 18 unpatentable (challenged references included Pruss and Keeler for anticipation and Coates in view of Hetrick for obviousness). https://ipverse.greyb.com/ptab-web/cases/case-details/IPR2015-01247
• Estoppel ruling: The W.D. Wis. court (Apr. 18, 2017) applied §315(e)(2) estoppel broadly, barring Meyer from re‑asserting both instituted grounds and grounds not raised in the IPR petition, while following Shaw Industries as to petitioned‑but‑non‑instituted grounds.
• Federal Circuit: appeal docketed as No. 2017‑1514.

Uncertainty Flags

1. No 2026 CAFC docket for 6928757 was surfaced; the documented appellate matter is the 2017 appeal. If you have a specific 2026 docket number, I can search it directly.
2. Claim 3's printed text appears incomplete/truncated in both Google Patents and Justia, lacking an antecedent recitation of the mount frame and first latch element. I did not locate an authoritative printed copy (e.g., the USPTO PatentCenter PDF of the granted patent) to confirm the claim's exact wording — recommend verifying against the official grant document.
3. Claims 13 and 14 appear textually identical in the sources retrieved; this may be a rendering artifact of the source databases rather than the printed patent.
4. Assignee chain is complex (Douglas Dynamics LLC → New DD, LLC → Douglas Dynamics, L.L.C., plus security interests to Credit Suisse and JPMorgan Chase, later released, plus a 2015 quitclaim from Batesville Services, Inc.). Google Patents lists current assignee as "NEW DD DELAWARE LLC LLC / Douglas Dynamics LLC," which it explicitly notes "may be inaccurate."

I'll research litigation involving US 6928757. Let me start with several targeted searches.

Let me dig deeper into the specific district court case, the Federal Circuit appeal, and any other suits involving this patent.

Let me check the litigation databases and look for any other cases involving this patent.

Litigation involving U.S. Patent No. 6,928,757

I searched the Stanford NPE Litigation Database, the Unified Patents litigation/PTAB portals, RPX Insight, the PTAB (PTACTS) docket, CourtListener/Justia, and secondary legal-press coverage. Below is what the records support. Note on scope: I found only one piece of Article III patent litigation in which US 6,928,757 was asserted, plus a directly related PTAB proceeding and its Federal Circuit appeal.

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1. Douglas Dynamics, L.L.C. v. Meyer Products LLC

Sources: Stanford NPE database (https://npe.law.stanford.edu/patent/6928757), RPX Insight litigation document (First Amended Complaint, https://insight.rpxcorp.com/litigation_documents/[11507428](/patent/11507428)), UniCourt docket summary (https://unicourt.com/case/rc-db1-douglas-dynamics-llc-v-meyer-products-llc-[885265](/patent/885265)).

Key development (April 18, 2017 estoppel ruling): Following the Federal Circuit's Shaw Industries Group, Inc. v. Automated Creel Systems, Inc., 817 F.3d 1293 (Fed. Cir. 2016), Judge Peterson held Meyer was estopped from asserting (a) the grounds instituted in the IPR, and (b) non-petitioned grounds it reasonably could have raised, but was not estopped as to grounds it petitioned but the PTAB declined to institute. Douglas Dynamics, LLC v. Meyer Prods. LLC, No. 14-cv-886-JDP, 2017 WL 1382556 (W.D. Wis. Apr. 18, 2017). Sources: VitalLaw (https://www.vitallaw.com/news/patent-w-d-wis-meyer-estopped-from-asserting-certain-invalidity-defenses-in-infringement-suit-by-douglas/ipm01ca45d98e7cb51000abdc90b11c18c90205), Patently-O (https://patentlyo.com/2017/04), Goodwin PTAB Trial Tracker (https://www.goodwinlaw.com/en/insights/publications/2017/04/04_27_17_ptab-trial-tracker-issue-4).

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2. Meyer Products LLC v. Douglas Dynamics, L.L.C. — PTAB IPR2015-01247

Although not an Article III lawsuit, this is a contested adversarial proceeding on the '757 patent and is central to the litigation history:

Sources: GreyB/IPVerse (https://ipverse.greyb.com/ptab-web/cases/case-details/IPR2015-01247), PTACTS records (https://ptacts.uspto.gov/ptacts/public-informations/petitions/[1462197](/patent/1462197)/...), Douglas Dynamics Patent Owner Response and Oral Argument presentation (same PTACTS docket).

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3. Meyer Products, LLC v. Douglas Dynamics, L.L.C. — Federal Circuit No. 2017-1514

Source: Federal Circuit order (docketed via PTACTS: https://ptacts.uspto.gov/ptacts/public-informations/petitions/1462197/...), and the Google Patents litigation listing for US6928757 referencing CAFC case 17-1514.

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4. Related but not an assertion of the '757 — flag for caution

I also found Meyer Products LLC v. Douglas Dynamics, L.L.C., No. 1:15-cv-00900-DAP (N.D. Ohio), which is identified as a "related case" to a different IPR, IPR2015-01839, involving U.S. 6,265,829 (a Meyer patent). That dispute concerns Meyer's patents asserted against Douglas — i.e., the parties are reversed, and the patents-in-suit appear to be different from the '757. I could not confirm that US 6,928,757 was at issue in the Ohio case, so I do not list it as '757 litigation. Source: Vernyuk declaration, IPR2015-01839 (https://www.docketalarm.com/cases/PTAB/IPR2015-01839/...).

Similarly, the well-known Douglas Dynamics, LLC v. Buyers Products Co. litigation (W.D. Wis., No. 3:09-cv-00261; Fed. Cir. 2013, 717 F.3d 1336) involved U.S. Re. 35,700, U.S. 5,353,530 and U.S. 6,944,978 — not the '757. Do not conflate it with the '757 record.

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Summary

• One district court patent infringement suit asserting US 6,928,757: Douglas Dynamics, L.L.C. v. Meyer Products LLC, No. 3:14-cv-00886 (W.D. Wis., filed Dec. 22, 2014).
• One PTAB inter partes review on the same patent: IPR2015-01247 (filed May 21, 2015; FWD Nov. 25, 2016 upholding the challenged claims).
• One Federal Circuit appeal from that IPR: No. 2017-1514, dismissed June 1, 2017 by agreement.
• No other litigation asserting US 6,928,757 appeared in the databases searched (the Stanford NPE database lists only the single W.D. Wis. case).

Caveats (per your strict rules): I have not auto-corrected any identifiers; all numbers are quoted as found. The final disposition of 3:14-cv-00886 (judgment, settlement, or dismissal) was not verifiable in the sources retrieved — the latest confirmed substantive event I found is the April 18, 2017 estoppel order. A PACER/CourtListener docket pull for the full docket would be the appropriate next step if you need the termination date and outcome. The patent is now listed as Expired – Lifetime, with anticipated expiration October 6, 2020 (20 years from the Oct. 6, 2000 priority date).

I'll reconcile the "no PTAB activity" default against the IPR2015-01247 reference in the patent record, which needs verification.

Meyer Products (not Unified Patents) filed it. Now the appeal and any sibling IPRs.

Let me confirm there are no additional IPRs on the '757 patent and pin down the FWD citation.

⚠️ Source-of-record conflict (read first)

The structured "PTAB proceedings on file" block states the ODP API returns no AIA trial proceedings for US 6,928,757. That ingest is incomplete. The patent record provided in this prompt itself contains a litigation/PTAB entry — "PTAB case IPR2015-01247 filed (Final Written Decision)" — with a link to Unified Patents' PTAB dataset. Public documents (PTAB FWD, hearing transcript, CAFC order, and the parallel district-court estoppel order) confirm the proceeding. I have therefore built the analysis from the PTAB record itself rather than the empty ODP payload.

Two data-hygiene notes:

• "Unified Patents" is the data provider on the Google Patents page, not a party. The petitioner of record is Meyer Products, LLC. No defensive aggregator is in this chain.
• One secondary source renders the case as "(PTAB, Feb. 16, 2012)" — a date typo; the proceeding was filed 2015-05-21. Ignore that citation.

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Proceedings overview

One (1) AIA trial proceeding on file: 0 active, 0 with claims invalidated, 1 in which every challenged claim was sustained, 0 settled, 0 outright institution denials (1 partially instituted — 3 of 7 proposed grounds instituted).

Bottom-line defensive posture: the patent is not "hardened by attrition" — it is simply un-hit. Every challenged claim (1, 4–7, 18) survived the only IPR on the merits, and the Federal Circuit never reviewed that decision (appeal dismissed by agreement). The real defensive lever is not the PTAB outcome at all: the '757 patent reached its anticipated expiration on 2020-10-06 and is recorded as Expired – Lifetime. Any demand letter citing 6,928,757 today is, at best, a past-damages claim for pre-2020 conduct, and any infringement theory that depends on live injunctive leverage is unsupportable.

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IPR2015-01247 — Meyer Products, LLC v. Douglas Dynamics, L.L.C.

• Type: Inter Partes Review (35 U.S.C. §§ 311–319). Pre-AIA patent (effective filing 2000-10-06), so IPR was the only available AIA vehicle — PGR and CBM were unavailable (patent predates 2013-03-16; snowplow mounting assemblies are not covered business methods).

• Filed: 2015-05-21

• Status: Final Written Decision (terminated). Ipverse records the termination date as 2016-11-25; the PTAB docket's document label reads "Termination Decision," but the document itself is styled FINAL WRITTEN DECISION — 35 U.S.C. § 318(a) and 37 C.F.R. § 42.73. The FWD was entered within the statutory one-year deadline from institution (institution 2015-12-09 → FWD 2016-11-25, ~352 days).

• Judge panel: Michael W. Kim, James A. Tartal, and James A. Worth, Administrative Patent Judges. Judge Worth authored the FWD. Petitioner counsel: Steven M. Auvil (Squire Patton Boggs). Patent Owner counsel: Aaron T. Olejniczak (Andrus Intellectual Property Law).

• Petition grounds (Meyer proposed seven grounds of cancellation; the Board instituted on three):

  Ground	Reference(s)	Basis	Claims challenged
  1 (instituted)	Pruss	§ 102	18
  2 (instituted)	Keeler	§ 102	18
  3 (instituted)	Coates in view of Hetrick	§ 103	1, 4–7, 18
  — (not instituted)	Pruss in view of Kost or Watson	§ 103	1, 4–7, 18
  — (not instituted)	Coates + Hetrick, Kost, or Watson	§ 103	1, 4–7, 18
  — (not instituted)	Keeler (as to additional claims, e.g., claim 6)	§ 102	6
  See W.D. Wis. Case No. 3:14-cv-00886, Dkt. 68 (2017-04-18), at 3–4 (reciting petitioned vs. instituted grounds). No § 112 grounds were asserted.

• Institution decision: Partially instituted — 2015-12-09. The Board found a reasonable likelihood as to the three grounds above and denied institution on the remainder, concluding Meyer's petition did not show a reasonable likelihood of prevailing on the non-instituted grounds. Meyer filed a request for rehearing of the institution decision, which was denied (Paper 13).

• Final Written Decision (2016-11-25) — claim-level verdict:

  "For the reasons that follow, we determine that Petitioner has not shown by a preponderance of the evidence that claims 1, 4-7, and 18 of the '757 patent are unpatentable."

  • Claim 1 (independent) — SUSTAINED / patentable
  • Claim 4 (independent) — SUSTAINED
  • Claim 5 (depends from 4) — SUSTAINED
  • Claim 6 (independent) — SUSTAINED
  • Claim 7 (depends from 6) — SUSTAINED
  • Claim 18 (independent) — SUSTAINED (over all three instituted grounds: Pruss § 102, Keeler § 102, and Coates + Hetrick § 103)

  No claim was canceled. Nothing was held unpatentable. The dispositive limitation across grounds was the "single assembly" / "one assembly" requirement (claims 1, 4, 6, 18). At the 2016-08-11 oral hearing, Patent Owner argued, and the Board accepted, that Pruss and Keeler disclose only piecemeal removal — e.g., "what Pruss teaches is that you have this piece of removal of the plow structure… it's not removal as a single assembly" — and that the Coates + Hetrick combination failed to disclose an A-frame and the required pivotal connections. Douglas also prevailed on objective indicia (commercial success of the UltraMount "pivot bar," copying, industry praise), supported by its expert Dr. Alexander Slocum (MIT) against Meyer's expert Mr. Smith, a former Meyer employee.

  • FWD PDF (docketalarm mirror): https://www.docketalarm.com/cases/PTAB/IPR2015-01247/Inter_Partes_Review_of_U.S._Pat._6928757/docs/11-25-2016-Board/Termination_Decision_Document-47-Termination_Decision_Document.pdf
  • Oral hearing transcript (2016-08-11): https://www.docketalarm.com/cases/PTAB/IPR2015-01247/Inter_Partes_Review_of_U.S._Pat._6928757/docs/09-20-2016-Board/Hearing_Transcript-46-Record_of_Oral_Hearing.pdf

• Settlement / termination: None in the IPR. The IPR ran to a merits FWD; there was no adverse-judgment termination and no public settlement of the proceeding. (A separate protective-order dispute arose when Douglas sought to use documents produced under a district-court protective order — the Board required Douglas to obtain permission from Meyer or the district court first; that is a discovery-side order, not a case disposition.)

• Appeal: Yes — appealed, then dismissed by agreement. Meyer Products, LLC v. Douglas Dynamics, L.L.C., No. 17-1514 (Fed. Cir.), appeal from the PTAB in Serial No. IPR2015-01247. On 2017-06-01, the Court issued a nonprecedential order dismissing the proceeding under Fed. R. App. P. 42(b) ("The parties having so agreed… Each side shall bear its own costs."). No merits ruling; the FWD stands unreviewed and unvacated. Order: https://ptacts.uspto.gov/ptacts/public-informations/petitions/[1462197](/patent/1462197)/download-documents?artifactId=z-kjqbG-RsnxwHDsgsSn-sl3t-IWy1fPo8qhNryU70sg-zyuKGXntJw (also retrievable on CourtListener under Fed. Cir. docket 17-1514).

• Defensive value: Meyer lost this IPR and paid for it twice. Under § 315(e)(2), as applied by Judge Peterson in Douglas Dynamics, LLC v. Meyer Prods. LLC, No. 3:14-cv-00886-JDP (W.D. Wis. 2017-04-18), Meyer was estopped from re-litigating in district court (a) all three instituted grounds and (b) all prior art it reasonably could have raised but did not petition — leaving it only the petitioned-but-non-instituted grounds (Pruss+Kost/Watson; Coates+Kost/Watson), i.e., arguments the Board had already deemed unlikely to succeed. Before you file an IPR on this patent, assume the same trap: this district court read § 315(e)(2) broadly, and there is no Federal Circuit merits decision reining that in.

  • Estoppel order: https://patents.harnessip.com/wp-content/uploads/2017/04/Douglas_v_Meyer.pdf

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Strategic summary

Claim status on US 6,928,757.

• CANCELED: none. There are zero canceled claims. The patent was never narrowed by any AIA trial.
• SUSTAINED (tested and upheld): claims 1, 4, 5, 6, 7, and 18 — one independent claim (1) covering the lift frame / trunnion / A-frame / motion-generating-device combination "attachable to and detachable from a vehicle as one assembly," plus independent claims 4 and 6 (both pivoting about transverse and longitudinal axes), their dependents 5 and 7, and independent claim 18 (longitudinal-pivot plow blade with single-assembly attach/detach).
• UNTESTED: claims 2, 3, 8, 9, 10, 11, 12, 13, 14, 15, 16, and 17. Notably, the entire stand-assembly claim family is untested — claim 15 (independently, continuously height-adjustable support stands with the locking-plate/dual-spring structure), claims 16–17, and independent claims 8 and 10 with dependents 9 and 11–14. If a modern assertion targets the adjustable-jack / drive-on mounting architecture, that theory has never been before the Board, and no IPR estoppel attaches to it for anyone.
• Expiration is the controlling fact. The patent record lists anticipated expiration 2020-10-06 (20 years from the 2000-10-06 priority date; the grant issued 2005-08-16). Status is Expired – Lifetime. Confirm the expiration certificate / any PTA in PAIR before relying on this, but on the record before me, the '757 patent's enforceable term ran out in October 2020.

Estoppel landscape.

The § 315(e)(2) bar runs against Meyer Products and its privies only — not against unrelated defendants. For a new defendant being asserted today, the practical bars are different ones: § 315(b) (a one-year window from service of an infringement complaint to petition for IPR) and the simple fact that the patent has expired, which removes both § 283 injunctive risk and any prospect of prospective relief. Where estoppel does bite — privity chains with Meyer, or a defendant who itself petitions — the W.D. Wis. ruling is the cautionary precedent: petition every ground you might ever want, because grounds you could have raised but didn't are gone, while only petitioned-but-non-instituted grounds survive Shaw. The surviving-art set from this IPR is essentially exhausted: Pruss, Keeler, Coates, Hetrick, Kost, Watson. Fresh art (e.g., the Slocum '436 reference that Meyer listed in its 2015 contentions but never petitioned) is the only genuinely open IPR lane — and it is now foreclosed to Meyer as a non-petitioned ground.

Pattern signals.

• One IPR on this patent, not a serial-petition campaign. Meyer filed a single petition (2015-05-21) and did not file a follow-on "Meyer 2" IPR on the '757 patent after losing — a departure from the serial-petition pattern the Board was beginning to scrutinize in 2017. Its only avenue left was district court, where it was largely shut down.
• Both parties were patent owners and petitioners across the family. Douglas itself petitioned against Meyer on a sibling patent — IPR2015-01839 (Douglas Dynamics, L.L.C. and Douglas Dynamics, Inc. v. Meyer Products LLC, U.S. Patent 6,265,829) — and there was a parallel N.D. Ohio action (Meyer Products LLC v. Douglas Dynamics, L.L.C., No. 1:15-cv-900). This is a two-competitor, multi-front snowplow war, not a troll campaign. The NPE Litigation Database classifies the sole '757 asserter (Douglas Dynamics) as a product company.
• Patent owner did not appeal. The petitioner appealed the FWD (17-1514) and then walked away from the appeal by joint stipulation on 2017-06-01. So the patent owner has never sought Federal Circuit review of anything on this patent, and there is no precedential CAFC construction of the '757 claims — claim scope is whatever the district court and the FWD said it is.

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Recommended next steps

If you are a defendant facing assertion of 6,928,757:

1. Lead with expiration, not validity. The patent record shows expired 2020-10-06. Verify in USPTO Patent Center/PAIR (expiration certificate, maintenance-fee history, any term adjustment) before anything else. If expired, there is no injunction (eBay/§ 283), no ongoing royalty, and § 286's six-year lookback from the date suit is filed will, as of 2026, capture an infringement window measured in days or nothing at all. That is a dispositive, cheap defense — cheaper than any IPR.
2. Do not buy the premise that this patent is "hardened." Nothing was canceled because nothing was ever invalidated. Claims 1, 4–7, and 18 survived a single, partially-instituted IPR marred by weak petitioner expert testimony (Meyer's expert was a former Meyer employee; Douglas's was an MIT professor with his own pivoting-plow patent). A better-financed, better-expert petition against untested claims 8–17 would present a materially different record — but see step 4 on whether it's worth the money on an expired patent.
3. If you do petition, petition everything at once. Douglas Dynamics v. Meyer (W.D. Wis. 2017-04-18) held that § 315(e)(2) estops a petitioner from raising prior art it "reasonably could have raised" but omitted from the petition. Grounds you list and lose at institution are preserved (per Shaw); grounds you never list are gone. Link the order in your file: https://patents.harnessip.com/wp-content/uploads/2017/04/Douglas_v_Meyer.pdf
4. Timing check. Any IPR you contemplate must be on file within one year of service of the complaint (§ 315(b)). PTAB's statutory deadline is one year from institution to FWD (§ 316(a)(11)) — this IPR went institution 2015-12-09 → FWD 2016-11-25, a useful benchmark for realistic scheduling.
5. If the FWD matters to your theory, quote it directly. The operative disposition sentence is: "For the reasons that follow, we determine that Petitioner has not shown by a preponderance of the evidence that claims 1, 4-7, and 18 of the '757 patent are unpatentable." Do not characterize it as a validity affirmance beyond that — the Board decided unpatentability, not validity, and the CAFC expressly declined to review it (dismissed 2017-06-01 under FRAP 42(b), nonprecedential).

Nothing is active on the PTAB docket for this patent. There is no pending IPR/PGR/CBM, no institution deadline, no oral hearing, and no FWD due date to calendar. If a docket search surfaces a new proceeding, it will be a fresh filing — most likely a § 315(b)-driven defensive petition — and it should be treated as a new matter, not a continuation of IPR2015-01247.

I'll research the assignment chain for US 6,928,757. Let me run targeted searches.

I found some reel/frame references embedded in the patent text. Let me dig deeper for the full assignment record.

Good — I now have several reel/frame numbers. Let me find the remaining links in the chain.

Research-limitation disclosure (read first)

I could not query the USPTO Patent Assignment Search / Assignment Center UI or its API directly — my only tool this session is a general web-search function, and I hit the search-step cap before I could retrieve correspondent-of-record fields or the reel/frame numbers for every leg of the chain. Accordingly:

• Reel/frame numbers below are given only where I actually retrieved them. Where I did not, I say so rather than inventing one.
• Correspondent (attorney/agent of record) fields: not retrieved. I flag this as a gap rather than guessing a firm.
• The bibliographic and legal-event rows from the Google Patents record (https://patents.google.com/patent/[US6928757B2](/patent/US6928757B2)/en) are treated as authoritative for dates, parties, and conveyance labels; reel/frame strings I confirmed via secondary indexing of the USPTO assignment records are noted individually.
• Verification entry point: https://assignmentcenter.uspto.gov/ and https://assignment.uspto.gov/patent/index.html (search patent number 6928757).

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Inventors

Confidence note: The patent's "Original Assignee" is Douglas Dynamics, LLC, which is consistent with all five being employees of the company at the Oct. 6, 2000 priority date. I found no independent evidence of individual employment terms, and no evidence of inventors departing within 12 months of filing. The "all inventors leave, then portfolio fire-sale" pattern you asked me to screen for is therefore not determinable from the sources I reached — I am not asserting it is absent, only that I could not test it.

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Original assignee

• Entity on the issued patent (2005-08-16): Douglas Dynamics, LLC (a Delaware limited liability company; "Original Assignee" per Google Patents).
• Line of business: Snow and ice control equipment — snowplows, spreaders, and related truck attachments. The '757 patent is directed to a snowplow mount/lift-frame assembly, i.e., the company's core product line, not a speculative filing.
• Did they ship a product embodying the claims? Yes. Douglas Dynamics commercialized the subject matter under its Western Products / FISHER brands, and its own 2014 suit asserts the family against a competing plow maker's "Ground Tracking Technology." Stanford's NPE Litigation Database classifies the 2014 action as "8 Product company" — i.e., not a troll assertion (https://npe.law.stanford.edu/patent/6928757).
• Current status of the ultimate parent: Douglas Dynamics, Inc. is a publicly traded operating company (NYSE: PLOW), which IPO'd in 2010; Douglas Dynamics, L.L.C. is its direct wholly-owned operating subsidiary (recited as such in the Apr. 18, 2011 Credit and Guaranty Agreement, Exhibit 10.1 to the Apr. 20, 2011 Form 8-K, https://ir.douglasdynamics.com/sec-filings/all-sec-filings/content/0001104659-11-021364/0001104659-11-021364.pdf). Not dissolved, bankrupt, or acquired.

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Assignment timeline

Note on date semantics: for the 2004–2011 cluster, Google Patents lists a single date per event (the recording date). For the JPMorgan liens I was able to recover both the effective/execution date and the recording date, and they differ; both are shown where known.

• 2000-10-06 — Not an assignment. Priority application Ser. No. 09/684,269 filed (later US 6,526,677); the '757 patent is a divisional of it.
• 2003-01-09 — Not an assignment. Divisional application 10/339,116 filed by Douglas Dynamics, L.L.C.
• 2004-04-09 (executed date not retrieved) / recorded 2004-04-09 — Reel/frame not retrieved
  • Conveyance: ASSIGNMENT OF ASSIGNORS' INTEREST
  • Assignor: Douglas Dynamics, L.L.C., a Delaware limited liability company
  • Assignee: New DD, LLC, a Delaware limited liability company
  • Correspondent: not retrieved
  • Context: internal reorganization / leveraged recapitalization — the operating entity's IP is pushed down into a newly formed acquisition vehicle ("New DD"), the classic first step of the 2004 buyout of Douglas Dynamics.
• 2004-05-19 / recorded 2004-05-19 — Reel/frame not retrieved
  • Conveyance: SECURITY INTEREST
  • Assignor: DDL Acquisition Corp. (DE); Douglas Dynamics Holdings, Inc. (DE); New DD, LLC (DE)
  • Assignee: Credit Suisse First Boston, acting through its Cayman Islands Branch, as Collateral Agent
  • Correspondent: not retrieved
  • Context: securitization — collateral grant in support of the acquisition debt.
• 2004-05-19 / recorded 2004-05-19 — Reel/frame not retrieved
  • Conveyance: SECURITY INTEREST
  • Assignor: New DD, LLC
  • Assignee: Credit Suisse First Boston, acting through its Cayman Islands Branch, as Collateral Agent
  • Correspondent: not retrieved
  • Context: securitization (second, parallel collateral record for the same financing).
• 2004-05-19 / recorded 2004-05-19 — Reel/frame not retrieved
  • Conveyance: CHANGE OF NAME
  • Assignor: New DD, LLC (DE LLC)
  • Assignee: Douglas Dynamics, LLC
  • Correspondent: not retrieved
  • Context: change of name only — "New DD, LLC" is renamed "Douglas Dynamics, LLC." This is the step that puts "Douglas Dynamics, LLC" on the face of the 2005 patent.
• 2004-? — Any recorded inventor→company assignment was not surfaced in the reassignment set (that set begins with the corporate events above). Flagged as a gap, not as an absence.
• 2007-07-23 (effective 2007-05-21) / recorded 2007-07-23 — Reel/Frame 019668/0230
  • Conveyance: SECOND LIEN PATENT SECURITY AGREEMENT
  • Assignor: Douglas Dynamics Holdings, Inc.; Douglas Dynamics, L.L.C.; Douglas Dynamics Finance Company; Fisher, LLC; and others
  • Assignee: JPMorgan Chase Bank, N.A.
  • Correspondent: not retrieved
  • Context: securitization — second-lien collateral package on the patented portfolio alongside the Credit Suisse first lien recorded the same day.
• 2007-07-23 (executed date not retrieved) / recorded 2007-07-23 — Reel/frame not retrieved
  • Conveyance: FIRST LIEN PATENT SECURITY AGREEMENT
  • Assignor: Douglas Dynamics Finance Company; Douglas Dynamics Holdings, Inc.; Douglas Dynamics, L.L.C.; Fisher, LLC
  • Assignee: Credit Suisse, Cayman Islands Branch
  • Correspondent: not retrieved
  • Context: securitization.
• 2011-04-20 / recorded 2011-04-20 — Reel/frame not retrieved
  • Conveyance: RELEASE OF SECURITY INTEREST IN PATENTS
  • Assignor: Credit Suisse, Cayman Islands Branch
  • Assignee: Douglas Dynamics, Inc.; Douglas Dynamics, L.L.C.; Douglas Dynamics Finance Company; Fisher, LLC
  • Correspondent: not retrieved
  • Context: release — clearing old collateral in connection with the April 18, 2011 refinancing.
• 2011-04-21 / recorded 2011-04-21 — Reel/frame not retrieved
  • Conveyance: RELEASE OF SECURITY INTEREST IN INTELLECTUAL PROPERTY (FIRST LIEN)
  • Assignor: Credit Suisse First Boston
  • Assignee: Douglas Dynamics Holdings, Inc., now known as Douglas Dynamics, Inc.; New DD, LLC; DDL Acquisition Corp.
  • Correspondent: not retrieved
  • Context: release of the 2004 Credit Suisse first-lien collateral.
• 2011-04-21 / recorded 2011-04-21 — Reel/frame not retrieved
  • Conveyance: RELEASE OF SECURITY INTEREST IN INTELLECTUAL PROPERTY (SECOND LIEN)
  • Assignor: Credit Suisse First Boston
  • Assignee: New DD, LLC; Douglas Dynamics Holdings, Inc., now known as Douglas Dynamics, Inc.; DDL Acquisition Corp.
  • Correspondent: not retrieved
  • Context: release of the 2004 Credit Suisse second-lien collateral.
• 2011-04-21 (effective 2011-04-18) / recorded 2011-04-21 — Reel/Frame 026165/0423
  • Conveyance: FIRST LIEN PATENT SECURITY AGREEMENT
  • Assignor: Douglas Dynamics, Inc.; Douglas Dynamics, L.L.C.; Douglas Dynamics Finance Company; and others
  • Assignee: JPMorgan Chase Bank, N.A.
  • Correspondent: not retrieved
  • Context: securitization — new first-lien package under the Apr. 18, 2011 Credit and Guaranty Agreement.
• 2014-11-? — Not an assignment. Douglas Dynamics, LLC v. Meyer Products LLC, No. 3:14-cv-00886 (W.D. Wis.) filed.
• 2015-06-01 / recorded 2015-06-01 — Reel/frame not retrieved
  • Conveyance: NUNC PRO TUNC QUITCLAIM DEED
  • Assignor: Batesville Services, Inc.
  • Assignee: Douglas Dynamics, L.L.C.
  • Correspondent: not retrieved
  • Context: title cleanup / chain-of-title correction. A nunc pro tunc deed is used to fix a defect retroactively. Batesville Services, Inc. is the Batesville casket business historically associated with Hillenbrand; why it held a residual interest in this patent is not established by anything I retrieved. This is the one genuinely unexplained link in the chain and it deserves a direct pull of the reel/frame document. It post-dates the 2014 suit and is therefore not a pre-litigation setup transfer.
• 2020-10-06 — Not an assignment. Anticipated statutory expiration (term end).
• 2021-06-10 (executed 2021-06-09) / recorded 2021-06-10 — Reel/Frame 056540/0138
  • Conveyance: RELEASE OF SECURITY INTEREST IN PATENTS PREVIOUSLY RECORDED AT REEL/FRAME 019668/0230
  • Assignor: JPMorgan Chase Bank, N.A., as Collateral Agent
  • Assignee: Douglas Dynamics, L.L.C.; Douglas Dynamics Finance Company; Douglas Dynamics Holdings, Inc.; Fisher, LLC
  • Correspondent: not retrieved
  • Context: release — the 2007 second-lien security interest is discharged under the June 9, 2021 Amendment No. 2 to the credit agreement.
• 2021-06-10 (executed 2021-06-09) / recorded 2021-06-10 — Reel/Frame 056540/0199
  • Conveyance: RELEASE OF SECURITY INTEREST IN PATENTS PREVIOUSLY RECORDED AT REEL/FRAME 026165/0423
  • Assignor: JPMorgan Chase Bank, N.A., as Collateral Agent
  • Assignee: Douglas Dynamics, Inc.; Douglas Dynamics, L.L.C.; Douglas Dynamics Finance Company; Fisher, LLC
  • Correspondent: not retrieved
  • Context: release of the 2011 first-lien security interest.

Net effect: after 2021-06-10 there is no security interest of record. Title of record sits with Douglas Dynamics, L.L.C. (the 2015 quitclaim grantee), a wholly-owned subsidiary of the publicly traded Douglas Dynamics, Inc.

Contradiction to flag: Google Patents' "Current Assignee" line reads "NEW DD DELAWARE LLC LLC / Douglas Dynamics LLC." That is inconsistent with the record above, where "New DD, LLC" ceased to exist in 2004 by change of name into Douglas Dynamics, LLC. Google expressly warns its assignee list "may be inaccurate." I treat the Douglas Dynamics, L.L.C. entry as the operative one and the "New DD Delaware LLC" entry as a database artifact — but it should be confirmed against the Assignment Center before being relied on.

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Timeline diagram

timeline
    title Ownership of US 6928757
    2000 : Priority application filed
    2003 : Divisional application filed
    2004 : Assigned to New DD LLC
         : Credit Suisse security interest
         : New DD renamed Douglas Dynamics LLC
    2005 : Patent US 6928757 issues
    2007 : JPMorgan second lien recorded
         : Credit Suisse first lien recorded
    2011 : Old Credit Suisse liens released
         : JPMorgan first lien recorded
    2014 : Douglas Dynamics sues Meyer
    2015 : Batesville quitclaim deed recorded
         : IPR2015-01247 filed
    2020 : Patent term expires
    2021 : JPMorgan liens released

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NPE / troll-pattern signals

1. Shell-entity transfer — NOT PRESENT. The only LLC-to-LLC hop is Douglas Dynamics, L.L.C. → New DD, LLC (recorded 2004-04-09), and New DD, LLC was renamed Douglas Dynamics, LLC four weeks later (2004-05-19 change-of-name record). A true NPE shell does not rename itself back into the operating brand. No "IP / Patents / Licensing / Holdings / Ventures" licensee entity ever appears. The "Holdings" entity in the chain (Douglas Dynamics Holdings, Inc.) is the public company's corporate parent, not a licensing vehicle.

2. Known asserter in the chain — NOT PRESENT. No assignee at any point matches Acacia, Marathon, Intellectual Ventures, IPNav, Wi-LAN, Conversant/Mosaid, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, or any Spangenberg entity. Every assignee in the chain is either (a) Douglas Dynamics/New DD, (b) a bank acting as collateral agent (Credit Suisse, JPMorgan Chase), or (c) Batesville Services, Inc. Independent corroboration: Stanford's NPE Litigation Database tags the sole suit on this patent with asserter category "8 Product company" (https://npe.law.stanford.edu/patent/6928757).

3. Repeat correspondent across the chain — UNCLEAR / NOT RETRIEVABLE. This is the signal I could not test: the correspondent-of-record field is exactly the data I failed to retrieve, and my tool budget expired before I could open the Assignment Center. I am not going to infer an attorney or firm. To close this out, pull the correspondence address for each of the nine recorded events, with priority on 019668/0230, 026165/0423, 056540/0138, 056540/0199 (bank-side filings, likely a single outside counsel) versus the 2004-04-09 and 2015-06-01 events (likely a different, company-side firm).

4. Cascading transfers — NOT PRESENT. There are four recordings inside a six-week window in 2004, but they are one corporate group acting on itself (one assignment down to a new vehicle, two collateral grants, one name change) — not a chain of unrelated LLCs sharing a correspondent address. There is no sequence of two or more third-party assignees inside 24 months. The 2004 cluster is a leveraged recapitalization, which is a financing event, not an assertion-enabling shuffle.

5. Pre-litigation transfer — NOT PRESENT. The 2014 W.D. Wis. suit was filed by Douglas Dynamics, LLC, an entity that had held record title continuously since the 2004 name change — a 10-year ownership, not a freshly-papered plaintiff. The only nearby assignment, the 2015-06-01 Batesville quitclaim, post-dates the suit and is a nunc pro tunc title cure, the opposite temporal signature of a pre-litigation setup transfer.

6. Bankruptcy fire-sale — NOT PRESENT. No Chapter 7/11 in the assignor's history surfaced; Douglas Dynamics instead completed an IPO in 2010 and remains listed (NYSE: PLOW). The 2004 Credit Suisse and 2007/2011 JPMorgan filings are ordinary secured financings of a going concern, and all were released, not foreclosed.

7. Privateering — NOT PRESENT. Douglas Dynamics is the manufacturer of the accused-against product line and sued a direct competitor (Meyer Products) itself, retaining counsel of record in the IPR (Aaron Olejniczak for respondent per IPR2015-01247). There is no operating-company → NPE → competitor-defendant structure. The PTAB proceeding ran the other way: Meyer was the petitioner, and the Board's Final Written Decision of 2016-11-25 rejected the challenge to claims 1, 4–7, and 18 (https://ipverse.greyb.com/ptab-web/cases/case-details/IPR2015-01247).

8. Defensive aggregator — NOT PRESENT. The chain never terminates at RPX, AST, LOT Network, Unified Patents, or OIN. It terminates at the operating subsidiary of a publicly traded manufacturer.

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Verdict

Operating-company assertion.

Justification: every recorded assignment in the chain is either an internal corporate step (Douglas Dynamics, L.L.C. → New DD, LLC, 2004-04-09, followed by the 2004-05-19 change of name back to Douglas Dynamics, LLC), a bank collateral grant and its later release (Credit Suisse 2004-05-19; JPMorgan 019668/0230 eff. 2007-05-21 and 026165/0423 eff. 2011-04-18, both discharged via 056540/0138 and 056540/0199 on 2021-06-09/10), or a title cure from Batesville Services, Inc. (2015-06-01 quitclaim). No licensing-only entity, no known NPE, and no defensive aggregator ever enters the record; the sole suit on the patent was brought in 2014 by the long-standing operating owner against a competitor, and Stanford's NPE database classifies the asserter as a product company. The two things that would move this off "operating-company" are unresolved data gaps, not contrary evidence: the correspondent-of-record fields (signal 3) and the reel/frame for the 2004, 2007 Credit Suisse, 2011 release, and 2015 events, plus the provenance of the Batesville Services quitclaim.

Verification link: https://assignmentcenter.uspto.gov/ (search patent 6928757; mirror at https://assignment.uspto.gov/patent/index.html)

I'll research the prior art cited for US 6928757, prioritizing the references the record shows were actually contested, plus the key prosecution citations.

Let me get the full citations and dates for the references contested in the IPR (Pruss, Keeler, Kost, Watson, Coates, Hetrick), which are the most probative prior art.

Let me nail down the exact patent numbers for the remaining IPR references (Keeler, Watson, Kost, Pruss, Hetrick).

I'll ground the obviousness analysis in the prior-art references listed on the patent page, and verify the key references (including the ones Meyer used in IPR2015-01247) before mapping them to the claims.

Let me verify a few more references that are directly on point for the "single-assembly attach/detach" and "receivers/horns" limitations, plus the latch references named in the '757 background.

Obviousness Analysis of U.S. Patent 6,928,757 under 35 U.S.C. § 103

Analyst note on scope and method. This analysis is built from the prior-art references listed on the US6928757B2 page you supplied (the "Citations (122)" / "Patent Citations (129)" lists, the references named in the '757 specification's own Background, and the references surfaced in the PTAB record for IPR2015‑01247 and on the litigation docket). Where I rely on a reference's title/abstract rather than its full text, I say so. I do not auto-correct anything; e.g., I treat "trunnion," "A‑frame," and the claim numbering exactly as printed, including the apparent defects in claims 3 and 13/14 flagged in the earlier sections.

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A. Legal framework and governing law

• Statute. The '757 issued from application 10/339,116 (filed Jan. 9, 2003), a divisional of Ser. No. 09/684,269 (filed Oct. 6, 2000, now US 6,526,677). Because the effective filing date predates March 16, 2013, pre‑AIA 35 U.S.C. § 103(a) governs. The Graham v. John Deere factors apply: (1) scope and content of the prior art; (2) differences between the prior art and the claims; (3) level of ordinary skill; (4) secondary considerations. KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007).
• Burden. In litigation, invalidity must be proven by clear and convincing evidence; at the PTAB, by a preponderance. The PTAB already ran one obviousness trial on this patent and upheld claims 1, 4–7, and 18 (FWD, Nov. 25, 2016, IPR2015‑01247). That result is a data point the reader must weigh against any proffered ground below.
• Prophetic vs. tested grounds. The combination actually tested was Coates in view of Hetrick (§103, claims 1, 4–7, 18) and Pruss/Keeler anticipation (§102, claim 18). (Per the Board's institution table: https://www.docketalarm.com/cases/PTAB/IPR2015-01247/…/Termination_Decision_Document.pdf.) I evaluate that combination and several untested alternatives that the page's prior art would support. An untested combination is not automatically stronger; it merely has not been rejected for the specific reasons the Board gave.

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B. Level of ordinary skill in the art (POSITA)

The field is vehicle‑mounted snowplow hardware (IPC E01H 5/06). A POSITA here would be a mechanical engineer (or equivalent experience) with roughly 2–4 years designing snowplow/implement mounting systems, or a technician with substantially more hands‑on experience in the same art. This matters because the '757's asserted advance is an arrangement of known mechanical couplings, not a new physical principle — a point that cuts toward obviousness.

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C. Claim-construction touchpoints that drive the § 103 result

Because the parties disputed these in the IPR, the obviousness outcome hinges on them:

1. "attachable to and detachable from a vehicle as one assembly" / "single assembly" (claims 1, 4, 6, 12, 18). Douglas argued this means the plow assembly (blade + A‑frame + lift frame + actuator) is designed to come off as a unit. That construction is what makes references that leave the lift cylinder on the truck (Coates) non‑anticipatory — and is why the Douglas‑owned prior patent Re. 35,700 / US 5,125,174, and US 5,485,690 (MacQueen), matter so much: they expressly disclose unit removal.
2. "trunnion" (claims 1, 4–8). Not limited to the exact drawn shape; functionally, a member pivotally connected to the lift frame about a transverse horizontal axis and to the A‑frame about a longitudinal horizontal axis.
3. Claims 1, 4–8, 18 are drawn to the snowplow assembly alone. The mount‑frame receivers/horns — the structure the specification touts as novel — is recited only in claim 3 (and only via "said first latch element of said mount frame"). So the broad independent claims cover a two‑axis floating plow assembly removable as a unit, which is the crux of the § 103 exposure.

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D. The prior-art universe, as mapped to the claim elements

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E. Ground‑by‑ground obviousness analysis

Ground 1 — Coates '906 + Re. 35,700 ("Watson"), and optionally + Hetrick '329 → claims 1, 4, 5, 6, 7, 18

This is the combination the Board actually tested (as "Coates in view of Hetrick or Kost or Watson").

• Coates '906 provides: a plow that pivots about a longitudinal horizontal axis (pivot shaft 98 in tube 92) and a transverse horizontal axis (cross beam 60 on bolts 78/90), plus a hydraulic lift (cylinder 54, lift arm 46, chain over sheave 50), and a drive‑on coupling ("The blade structure 94 is connected to the vehicle by simply driving the vehicle forwardly so that the pivot shaft 98 is received by the tube 92." — US3605906, col. 4:47‑50).
• Re. 35,700 / US 5,125,174 provides: the A‑frame + lift frame + actuator removable as a unit, with the A‑frame pivotally connected about a horizontal axis, and even the headlamp/lift‑frame arrangement (the '757's "pair of headlights" concept). Its abstract: "…can be attached to, and detached from, the mounting frame as a unit."
• Hetrick '329 supplies a vehicle‑side, hydraulically actuated latch that accommodates misalignment — the "drive‑on and latch" teaching.

Missing‑element gap. No single one of these discloses the '757's precise trunnion‑between‑lift‑frame‑and‑A‑frame geometry with the A‑frame pivoting on the trunnion about the longitudinal axis. Coates' "cross beam 60" is the functional analogue of the trunnion, but it is not connected to a lift frame that comes off with the plow; Re. 35,700 has no separately recited trunnion.

Motivation to combine (KSR). (i) Same field, same problem — mounting a snowplow to a truck quickly and letting the blade float. (ii) Both references address the same two objectives the '757 claims as benefits: quick attach/detach and blade conformance to terrain. (iii) The industry was demonstrably moving to "unitary" removable plows to cut front‑axle load and improve fuel economy — a benefit Re. 35,700 states in terms (reduced loading, retained fuel efficiency, protects the lift unit from the elements). (iv) Coates itself already teaches a drive‑on connection, so adding a unit‑removable lift frame is "the simple substitution of one known element for another to obtain its predictable advantage," and the result is a predictable mechanical assembly. (v) A POSITA would have a reasonable expectation of success because each sub‑system is independently operable and their combination is a rearrangement of bolted/pivoted joints, not a change in physics.

Against the ground. Douglas successfully argued below that Coates' disclosed principle of operation is to leave the cross beam and hydraulic cylinder on the truck and remove only blade + frame, and that converting Coates to a unit‑removable configuration would "change the basic principle" and defeat Coates' push‑arm stress distribution (Patent Owner Response, IPR2015‑01247, https://ptacts.uspto.gov/ptacts/public-informations/petitions/[1462197](/patent/1462197)/...). The Board credited that. This is the central weakness of Ground 1 and the reason I regard it as not clearly persuasive on the present record, at least as to the "single assembly" limitation and the trunnion/A‑frame geometry.

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Ground 2 — Re. 35,700 (primary) + Coates '906 or Slocum '436 / Valley '751 (secondary for the second axis) → claims 1, 4, 5, 6, 7, 18

Invert Ground 1. Take as the base reference the Douglas patent that already discloses "A‑frame + lift frame + actuator detachable as a unit" (Re. 35,700), and add the longitudinal‑axis float disclosed by Coates / Slocum / Valley. This avoids the "changes Coates' principle of operation" objection, because the base reference already teaches unit removal — the secondary reference is used only for the added, admitted‑known pivot.

• Motivation: the '757 specification itself concedes that plows rotating about both a longitudinal and a transverse axis are known (U.S. 3,605,906; 3,822,751; 4,821,436). A POSITA seeking to add the acknowledged "hugging/cleaner‑scrape" benefit to an already unit‑removable plow would combine them with a reasonable expectation of success.
• The '757's "hugging action … cleaner scrape … even cutting‑edge wear" is the classic articulation of a predictable benefit of a known pivot, which KSR treats as an obvious design choice.

This framing is materially stronger against claim 18 (which does not even require a trunnion — only a lift frame, a blade pivotable about a longitudinal horizontal axis, a motion generator, and single‑assembly removal), but I flag that this specific ordering was not the ground the Board rejected, so its strength is partly untested. The Board's rejection was of a different combination.

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Ground 3 — Re. 35,700 or MacQueen '690 + Stanford '825 + Drott '884 → claims 8, 9, 10, 11, 12, 13, 14

Claims 8–14 add (a) an independently height‑adjustable, and (b) continuously height‑adjustable, pair of stands.

• Re. 35,700 / US 5,125,174 discloses a support stand pivotally connected to the plow, movable between a storage position and a support position, with the express statement that the stand "can be used to adjust the height of the A‑frame when mounting the snowplow assembly."
• US 4,205,825 (Stanford) discloses a screw jack on a snowplow frame whose entire stated purpose is to "adjust the height of the frame as may be required to enable the frame to be reconnected to the truck" — squarely the '757's stated motivation ("such an adjustment feature … is advantageous when parking snowplow assembly on unlevel ground").
• US 3,150,884 (Drott) shows a stand that swings into and out of support position (the '757 Background cites it).
• Independence of the two stands follows automatically from providing one stand per side on a frame that can tilt; nothing in the references forecloses it, and the '757's own text says the two stands "may require extending one … further than the other … depending on the terrain."

Motivation. A plow parked on a hill needs both sides supported; giving each side its own stand with its own adjuster is the natural, predictable solution, and Stanford supplies the continuously adjustable (screw) mechanism. This ground is, in my view, the strongest of the set for claims 8–14, because the references are numerous, directly on point, and independent adjustability is a near‑inevitable design consequence of using one stand per side.

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Ground 4 — Coates '906 / 3,987,562 Deen + Hickey‑style spring latches → claim 3

Claim 3 (as printed) recites a stand pivotable between down/up positions carrying a second latch element that engages a first latch element on the mount frame, engaged when the stand is up. The prior art that best maps to "a latch element automatically engaged by the mounting motion" is:

• US 3,987,562 (Deen / American Equipment) — jaws close on hitch pins and spring‑loaded locking pins automatically lock the jaws on coupling. See description of spring 102 and automatic lock pin engagement (https://www.freepatentsonline.com/3987562.html).
• US 3,605,906 (Coates) — locking means 104 secures pivot shaft 98 in tube 92.
• US 3,150,884 (Drott) — the stand is swung/latched into place as the vehicle engages the plow.

Caveat: claim 3's printed text is truncated and lacks antecedent basis for "said mount frame" and "said first latch element" (flagged earlier). For § 103 purposes that is a § 112 defect, not an obviousness point; but it means claim 3 cannot be reliably charted, and I decline to assert a confident mapping. Treat Ground 4 as incomplete.

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Ground 5 — US 3,987,562 + US 4,205,825 / US 5,368,409 → claims 15, 16, 17

Claims 15–17 define the stand's hardware: a bracket with two holed plates, a leg sliding through them; a pivoting locking plate with a hole through which the leg passes, with a handle; a first spring urging the edge of the locking‑plate hole into "bite" with the leg; a second spring biasing the leg relative to the bracket.

• A spring‑biased locking member that engages a sliding member and is released by a handle/ring is shown in US 3,987,562 (spring‑loaded pin 101 + ring 104; spring 102).
• US 5,368,409 (Pitney Bowes) is cited on the '757 face and discloses a latching mechanism with independent biased latching members — relevant to the "first spring / second spring" architecture.
• US 4,205,825 (Stanford) shows the adjustable‑height stand environment into which such a mechanism would be placed.

Honest limitation. I do not find, in the reference set on this page, a square disclosure of the specific "edge‑of‑hole bites the leg" cam‑lock with two compression springs and a C‑shaped bracket. A challenger would likely need either an additional reference outside the cited list (the mechanism is a common adjustable‑stand/crutch‑type cam lock) or a POSITA‑general‑knowledge argument. Under KSR that is permissible, but it makes Ground 5 the least certain for the dependent claims. (Note also that the handle plate 112 / C‑bracket 115 structure is essentially a Hollaender‑type cam clamp — ubiquitous in tubular‑stand art.)

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F. Why a POSITA would combine — consolidated rationales

1. Same field, same problem, same inventors' admitted art. Every primary reference here is snowplow mounting art; the '757 Background concedes the two‑axis pivot (Coates, Valley, Slocum), the pivotable lift stand (Re. 35,700, Drott), and the latch mechanism (5,031,927, 3,987,562) as known.
2. Predictable mechanical result. The claims recite couplings (trunnion, pivots, stands) whose combination merely aggregates known motions (transverse float for lift, longitudinal float for terrain, up/down for storage). KSR: combination of known elements with predictable results.
3. Market/design pressure for "one‑unit" removable plows. Both the '757 and Re. 35,700 articulate the same commercial drivers (leave nothing bulky on the bumper; reduce front axle load; protect the hydraulic unit). A POSITA had every incentive to marry that with Coates' drive‑on geometry.
4. The problem was known and the solution conventional. "Alignment on uneven ground" is exactly the problem Stanford '825 was written to solve (1953 patent lineage; reissued Douglas patents). When the problem is recognized and the piece parts are known, KSR lowers the obviousness bar.

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G. The counterarguments that defeated Ground 1 (important)

1. Change in principle of operation / teaching away. Douglas's expert (Dr. Slocum, MIT) and even Meyer's expert agreed that Coates is designed to remove only the blade and frame means, leaving the cross beam 60, side plates 38, and cylinder 54 on the truck; forcing unit removal would undercut Coates' push‑arm stress distribution (Patent Owner Response §VI, and Rebuttal Declaration ¶¶63, 115‑117, https://ptacts.uspto.gov/ptacts/public-informations/petitions/1462197/...). The Board credited this and held the combination nonobvious.
2. No suggestion of the trunnion/A‑frame geometry. Douglas argued Coates and Hetrick together do not suggest "a trunnion connected to a lift frame and an A‑frame pivotally attached to the trunnion … so that the A‑frame can pivot along a longitudinal, horizontal axis … and settle … prior to lowering the stands." (Rebuttal Decl. ¶173.)
3. Claim‑construction lever. The narrow construction of "single assembly" is doing much of the work; if the term were construed functionally (capable of unit removal), Grund 1 and Ground 2 strengthen considerably.

I should be explicit: on the tested record, the Board's nonobvious judgment means a challenger would need new evidence (a reference squarely disclosing the trunnion‑mounted longitudinal float on a unit‑removable lift frame) or a different claim construction to prevail. My Grounds 2–4 are efforts at that, but none is proven.

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H. Secondary considerations (the patent owner's strongest material)

The PTAB record contains substantial objective evidence that a court would weigh under Graham prong (4). Douglas introduced evidence of (a) long‑felt need for mounting on uneven ground, (b) industry praise for the "pivot bar" (ULTRAMOUNT; e.g., "the pivot bar on Western's ultramount has been a great feature"; "swivel lets plow stay on the ground on uneven ground"), (c) commercial success of assemblies incorporating the longitudinal‑pivot feature, and (d) copying/competitor failure — Meyer's own "Ground Tracking Technology" marketing is alleged to tout the same contour‑following benefit (see PTACTS trial record, https://ptacts.uspto.gov/ptacts/public-informations/petitions/1462197/...). All four, if properly nexused to the longitudinal‑pivot limitation, cut strongly against a § 103 holding — and are the likely reason the Board upheld claims 1, 4–7, 18.

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I. Bottom line

Overall. The '757 sits in a mature art with multiple acknowledged solutions to each recited element, so a prima facie § 103 case can be articulated for every independent claim. But the single combination the Board actually tested (Coates + Hetrick / Kost / Watson, claims 1, 4–7, 18) failed, and the objective evidence of nonobviousness in the IPR record is substantial. On the record available to me, I would rate the patent more likely than not to survive a renewed § 103 challenge, with claims 8–14 (adjustable stands) being the most exposed and claim 18 the next.

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J. Uncertainty flags (do not treat these as resolved)

1. Pruss and Keeler are referenced in IPR2015‑01247 as § 102 art against claim 18, but I could not confirm their patent numbers from the sources retrieved; I have deliberately not assigned numbers. The trial record refers to "Pruss 1" and "Pruss 2" (two embodiments).
2. Watson in the IPR appears to be US 5,125,174 / Re. 35,700 (inventors Watson, Fechter, Doornek) — consistent with the Espacenet bibliographic record — but I flag the inference rather than assert it. Kost is a separate reference I could not identify.
3. Hetrick '329 is US 4,236,329 ("Detachable blade mounting device"), which I confirm appears both in the Re. 35,700 citation list and in the '757's own "Patent Citations" list — but I am relaying the IPR's characterization of its disclosure, not my own review of the full text.
4. US 6,050,008 (Doornek et al.) surfaced in a third‑party WO search report as an X reference on closely related claims (two‑axis A‑frame/support‑frame arrangements) and shares a surname with a '757 inventor. I could not verify its disclosure or inventor identity and therefore do not rely on it; if it does disclose the trunnion‑mounted longitudinal float on a unit‑removable lift frame, it would materially strengthen Ground 2 and should be verified against the grant text.
5. Claim 3 and the identical claims 13/14 remain as flagged in the earlier sections; the § 112 defects there affect chartability but not the § 103 conclusions.
6. All reference characterizations drawn from titles/abstracts only are marked above; a full‑text pull of Hetrick '329, Slocum '436, Valley '751, and Deen '562 would be required before anything here is reduced to a formal invalidity contention.